Dear Franklin You are making a bit of confusion between ferromagnetic systems (Fe, Ni, Co ,...), and paramagnetic systems (O2, among many others). Both kinds of system ARE magnetic, and generally require spin polarized calculations. Regarding k-points, molecules have electronic levels flat in the Brillouin zone (if you do not know what does such a statement mean and imply, a solid state physics textbook may help...). Thus, calculations of molecules do not depends on k-points, as long as the box is enough large to minimize the interaction between periodically repeated images of the molecule. Solids, like ZnO, are (in a quite rough manner of speaking...) characterized by dispersed electronic bands instead, and require to check the convergence with respect to the k-point mesh. HTH (another cup, please, and with cream...:-))
On Wednesday 25 July 2012 12:41:06 Franklin Zhan wrote: > Dear Prof. Giannozzi, > It is great to hear from you. > In my mind, only when we are dealing with some magnetic materials > calculation, such as Ni, iron, the spin polarization is taken into > account. However, O2 molecule is not magnetic material, thus I do not know > why we need to take the spin polarization into consideration. > > > > Best regards, > > > > > Franklin Zhan > > Ph.D student > School of Mechanical and Aerospace Engineering, > Nanyang Technological University, Singapore. > > > From: giannozz at democritos.it > > Date: Wed, 25 Jul 2012 12:25:51 +0200 > > To: pw_forum at pwscf.org > > Subject: Re: [Pw_forum] how to calculate and plot HOMO or LUMO isosurface > > > > On Jul 25, 2012, at 12:20 , Franklin Zhan wrote: > > > since O2 is not a magnetic system > > > > I beg your pardon? > > > > > > You seem not to be a chemist...:-) > > > > The ground state of an O2 molecule is a triplet one, with 7 up > > > > > > valence electrons and 5 down. > > > > P. > > --- > > Paolo Giannozzi, Dept of Chemistry&Physics&Environment, > > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > > Phone +39-0432-558216, fax +39-0432-558222 > > > > > > > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la propri?t?, la s?ret? et la r?sistance ? l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <giuseppe.mattioli at ism.cnr.it>
